Reversible refrigerating systems



March 28, 1961 G. MUFFLY 2,976,698

REVERSIBLE REFRIGERATING SYSTEMS Original Filed Sept. 19, 1951 3Sheets-Sheet 1 E V149 j) GOA/D.

32 4/6 7 E- BY M My (9 %y/iq March 28, 1961 G. MUFFLY 2,976,698

REVERSIBLE REFRIGERATING SYSTEMS Original Filed Sept. 19, 1951 3Sheets-Sheet 2 IIIIII' I I IN V EN TOR.

7 4 672/121 fl/zzf/Zg rwRA zsva March 28, 1961 G. MUFFLY REVERSIBLEREFRIGERATING SYSTEMS 5 Sheets-Sheet 5 Original Filed Sept. 19, 1951 INV EN TOR. G Ze/W? )fzzffl BY REVERSIBLE REFRIGERATING SYSTEMS GlennMufliy, 1541 Crestview Drive, Springfield, Ohio Original applicationSept. 19, 1951, Ser. No. 247,239,

now Patent No. 2,844,945, dated July 29, 1958. Divided and thisapplication Sept. 11, 1957, Ser. No. 683,335

15 Claims. (Cl. 62-460) This application is a division of my copendingUnited States application Serial Number 247,239, filed September 19,1951, issued July 29, 1958, as Patent No. 2,844,945, and relates todefrosting and to reversing the direction of fluid flow with or withoutthe direction of compressor rotation being reversed.

There is a need for a reversible compressor and/or valve mechanism inreverse-cycle refrigerating and air conditioning systems, andparticularly for defrosting freezer evaporators of two-temperaturerefrigerators.

No refrigeration compressor now on the market is suitable for reversingrefrigerant flow, hence complicated valve arrangements are coming intouse. Piston type compressors continue to pump in the same direction whentheir direction of rotation is reversed. Rotary compressors in which thepiston or rotor is carried by a crank pin or eccentric require dischargevalves which prevent operation of the compressor in reverse. The gear orlobed impeller type of compressor reverses its direction of fluid flowwhen the direction of rotation is reversed, but this type has not provensatisfactory and is not currently in production in the refrigerationfield because of noise and the fact that gas leakage increases withwear. The type of rotary compressor in which a rotor is eccentricallylocated with respect to its cylinder and mounted concentric-ally on thedrive shaft usually carries one or more sliding radial vanes which sweepthe clearance space. direction of pumping when reversed in rotation ifequipped with three or more vanes, but such reverse pumping isinefficient since the suction and discharge ports are not suited forreversing their functions.

When four or more radial vanes are carried by the rotor it is practicalto dispense with the usual check valves located in the inlet anddischarge ports, but for best results the discharge port should besmaller than the suction port and the latter should extend fartheraround the cylinder in order to allow proper filling of the displacementspace. This has prevented the development of a satisfactory reversiblecompressor.

It is an object of this invention to provide a compressor which reversesits direction of pumping when its direction of rotation is reversed andhas good efiiciency when operated in either direction.

Another object is to provide a compressor having a pair of ports whichinterchange their functions of inlet and discharge when the compressorrotation is reversed and to provide an additional port which serves asan auxiliary inlet port for both directions of rotation.

Another object is to provide self-actuating valve means for connectingthe last mentioned port with the suction conduit and shifting thisconnection to another suction conduit when the compressor rotation isreversed.

Another object is to provide a compressor which allows high and low sidepressures to equalize when idle.

Another object is to provide a valve mechanism responsive to thestarting of the compressor in either of This latter type of compressordoes reverse its Fatiented Mar'. 28, 1961 two manners to close and openthe proper ports in relationship to the direction in which thecompressor has been started.

Another object is to provide reverse-cycle defrosting of a freezerevaporator in a primary system which is combined with a secondary systemof which the evaporator is not to be defrosted.

Another object is to'provide a pair of opposed check valves sointerconnected as to cause the closing of one valve to open the otherwhen the system is started and to allow each valve to assume a partlyopen position each time the compressor is stopped.

Another object is to provide a check valve and its as sociated chamberso proportioned that when the valve is in its idle partly open positionit nearly closes the pas. sage so that a slight ilow of fluid will causethe check valve to close, yet when the valve is fully opened it oifersno serious obstruction to the flow of fluid in the direction which wouldotherwise tend to close the valve.

Another object is to provide for defrosting the colder evaporator onlyin a multiple-temperature system using either a conventional compressoror a compressor with the multiple-effect or dual-suction arrangementwhich provides two distinct suction pressures.

Still another object is to achieve the utmost simplicity in atwo-temperature system with automatic defrosting of the colderevaporator, such defrosting being accomplished automatically by a simplereversal of motor rotation or shifting of valves without affecting thetemperature of the space cooled by the warmer evaporator.

In the drawings:

Fig. 1 is a diagrammatic view of a two-temperature refrigerating systememploying a new type of compressor and valve mechanism which combine toreverse flow in the system.

Fig. 2 is a longitudinally sectional view of a compressor such asillustrated diagrammatically in Fig. l, but show-- ing the preferredarrangement of ports, with the constant inlet port at the top.

Fig. 3 is a sectional and diagrammatic view of a similar compressor asused in a heat-pump or reverse-cycle.

system with a reversible valve incorporated in the motorcompressor unitand arranged to control vapor flow instead of liquid flow.

Fig. 4 is a top view of a reversing valve mounted on the head of aconventional compressor, to provide reversal of both discharge andsuction where the compressor does not in itself reverse flow when itsdirection of rotation is reversed.

Fig. 5 is a detail sectional view on the line 5-5 of Fig. 4.

Fig. 6 is a diagrammatic view of a system similar to Fig. 1 but using areciprocating multiple-effect compressor and a clock switch to controlthe valves.

Fig. 7 is a diagrammatic view of a similar system but using aconventional compressor and having the electrically actuated valvesunder thermal instead of clock control.

Fig. 8 is a bottom view of a sealed motor-compressor unit designed foruse in a system having its high side on the rear wall of a two-zonerefrigerator to conserve space audaid in disposal of defrost water.

Fig. 1 shows the compressor 10 driven clockwise, which is the directionof rotation for defrosting the freezer evaporator 12 with hot highpressure refrigerant vapor, which condenses therein and flows throughthe restrictor tube 14 to the condenser 16, in which the condensedrefrigerant evaporates, and returns to the compressor at frostingoperation.

of the compressor and the path of refrigerant flow during thisdefrosting period are indicated by solid arrows.

At the completion of the defrosting operation the compressor rotationstops and then restarts in the opposite direction as indicated by thedotted arrow on the rotor 26. This causes the port 28 to serve as asuction inlet to the compressor, which draws refrigerant vapor from thefreezer evaporator 12 and discharges it at port 18 through the tube 30to the condenser 16. Liquefied refrigerant flows from the condenserthrough the vapor-lock restrictor 14 to the chamber 32 of the reversingvalve 34. The impact of the resulting jet of liquid refrigerant mixedwith its flash gas striking the vane 36 causes this vane to tilt uponits pivot 38, opening the valve 22 and closing the valve 40. Liquidrefrigerant now leaves the chamber 32 by way of the tubes 42 and 44after filling the lower portion of the chamber 32 with liquid. When asufficient pressure had developed within the tube 42 in excess of thepressure existing in the freezer evaporator 12 the Weighted check valve46 lifts and refrigerant liquid flows through the tube 48 into the lowertemperature evaporator 12, from which vapor flows through the tube 50 tothe inlet port 28 of the compressor.

It will be noted that the spacing ofthe ports 28 and 24 is such thatthey are always divided by one or more of the radial vanes 52, 54, 56,and 58 so that vapor withdrawn from the evaporator 12 is trapped in thespace between two vanes, such as 52 and 54-, before this space comesinto communication with the auxiliary inlet port 24, at which timehigher pressure suction vapor from the evaporator flows into the spacebetween these two vanes. This space reaches its maximum expansion at thetime the two vanes reach their symmetrical position straddling the port24, but due to the velocity of suction vapor in the tube 61 it willcontinue to flow from tube 60 into the compressor until approximatelythe cutofl? point at which the vane 54 cuts the compression space 011?from the auxiliary inlet port 24.

The trapped vapor is now compressed and delivered to the port 18, suchdischarge continuing until the vane 54 opens the port 18 to the nextcompression space between the vane 54 and the vane 56' There will besome reverse flow between the port 18 and these arcuate spaces, but withthe proper arrangement of ports and the proper number of blades therecan be no actual leak-back except the limited amount of unavoidableleakage past the working surfaces of the compressor.

The shaft 62 carrying rotor 26 is preferably the shaft of a twopolealternating current motor which, on 60 cycle current, will operate atabout 3400 to 3500 r.p.m. It is desirable to keep the motor diameterdown to a minimum for reasons which will appear later herein, hence inFig. 1 it is assumed that the rotor and stator of the motor are hiddenback of the compressor cylinder 64. The motor and compressor arepreferably enclosed within a sealed casing to which the tube 60 leadsand from which vapor flows into the port 24. The cylinder 64 is providedwith end plates or heads in the customary manner and it is preferredthat the ports 18, 24 and 28 be formed by recesses in one or both ofthese heads rather than as shown diagrammatically in the cylinder borein Fig. l. The blades of rotary compressors are often provided withsprings to hold them in engagement with the cylinder bore, but suchsprings may be omitted in this case because of the high speed ofrotation which provides ample centrifugal force to hold the bladesagainst the cylinder bore.

In order to prevent the development of a partial vacuurn in the slotback of a blade, which would interfere with the operation of centrifugalforce, and to prevent the accumulation of oil in a slot which wouldinterfere with the free movement of a blade, I have shown a counterbore65 connected with all of the slots by means of radial holes, which areindicated by'dotted lines.

When the motor is stopped with a considerable pressure differenceexisting between the tubes 36 and 50 the compressor is free to reverseits direction of rotation and act as a vapor-expansion motor until thesepressures are nearly balanced. It is desired that pressures within thesystem equalize during idle periods of the compressor and the tendencyof the compressor to act as a motor aids the electric motor in startingits reverse rotation when the controls of the system cause aninstantaneous switch from cooling to defrosting or vice-versa.

The housing 66 which encloses the weighted check valve 46 may beincorporated with the valve assembly 34 to eliminate the tubes whichconnect these two housings, but it may be preferred to keep themseparate so that the housing 66 can be located adjacent to the colderevaporator 12 while the valve assembly 3 is located adjacent to thewarmer evaporator 23*. neither case it is preferred that the internalvolume of the chamber 32 below the level of the various ports be kept ata minimum to conserve refrigerant liquid. All four of the portsconmeeting with the chamber 32 may be located at the same level, thoughshown at two different levels in Fig. 1 so that the refrigerant flowpaths can be more easily traced. The freezer evaporator 12 may belocated either above or below the Warmer evaporator 20 and the Weightedcheck valve 46 may be located either above or below the reversing valveassembly 34, hence this system is adaptable for use in a two-zonerefrigerator with the freezer compartment either above or below the mainfood compartment.

Fig. 1 illustrates the arrangement of ports and refrigerant passages forcooling a pair of evaporators simultaneously, one at a lower evaporatingpressure than the other. The condenser 16 receives refrigerant from bothevaporators while they are being cooled, but when the colder evaporator12 is being defrosted by reserve operation of the compressor the warmerevaporator 20 is not affected since it is isolated by the closed valve22.

A third evaporator 68, comprising a part of a secondary refrigeratingsystem, may be combined with this system by locating the secondarycondenser 70 in heat exchange with a portion of the evaporator 12, asindicated in Fig. 1. If a secondary system such as 68-7tl is used inplace of the warmer evaporator 20, or only one evaporator is required,the valves 34 and 46 may be eliminated, connecting the vapor-lockrestrictor 14 directly with tube 48. Such a system is illustrated inFig. 3. The elimination of evaporator 20 makes the port 24 available forwithdrawal of refrigerant vapor from the evaporator 12, but it is thenpreferred to stop it off from evaporator 12 during the defrostingperiod, as will be explained later with reference to Fig. 3. Thesecondary evaporator 68 will not be affected by the defrosting ofevaporator 12 since the heating of the secondary condenser 70 merelystops the flow of vapor from 68 to 70, thus trapping the entire chargeof secondary refrigerant in the evaporator 68.

Fig. 2 shows a preferred arrangement of the compressor of Fig. 1 withports in the end walls 72 and 74 instead of in the cylinder barrel 64.The auxiliary intake port 24 in the wall 74 is open to the interior ofthe sealed housing 76 and hence placed at the top to be above the levelof oil 78. The suction tube at} enters the housing on the far side ofthe motor 80 so that suction vapor from evaporator 20 aids in coolingthe motor. The ports 18 and 28 are formed in the end plate 72 whichcloses the housing. Tubes 38 and 50, connected with these ports, arebrazed to the end plate 72. An oil slinger 82, shown in the form of adrawn cup attached to the rotor of the acrea e motor, has two or morearms 34 which, in either direction of rotation, throw oil against thesheet metal baffle 86 which is attached to the plate 74 and arranged tocarry oil into the pocket 88, which leads to port 24 and also to theshaft through the hole 90.

The stator of the motor is pressed into the housing 76 and provided witha longitudinal oil passage 92 so that the level of oil 78 is maintainedon both sides of the motor. Four terminals of the motor winding, as 94of Fig. 2, are connected with a suitable reversing switch, as 96 in Fig.3, which may be operated manually, by temperature or pressure changes,by count of cycles or openings of cabinet or by a clock, for the purposeof starting the motor in either direction of rotation. In one closedposition of switch 96 one of the wires of the line may be connected withwires 97 and 98 while the other line wire is connected with 99 and 100.In the other closed position of switch 96 one of the line wires wouldthen be connected with 07 and 99 while the other line wire connects with98 and 100 for the reverse rotation of the compressor.

Referring now to Fig. 3, which shows a rotary compressor similar tothose of previous figures. This compressor is assumed to be of the opentype,i.e. not incorporated in a sealed unit, and to be connected withtwo heat exchangers 12 and 16 in series with the restrictor 14 betweenthem. The rotor 26, which is concentric with and driven by an electricmotor, carries four blades 52, 54, 56 and 58 which are free to slide intheir radial slots in the rotor so that they are held in contact withthe bore of cylinder 64 by centrifugal force whenever the compressor isoperating. Since there are no springs holding the blades in contact withthe cylinder bore, there are no check valves which remain closed whenthe compressor is idle and the compressor may be driven in eitherdirection by excess pressure in one of the lines 30 or 50, it is seenthat high and low side pressures will equalize very soon after thecompressor is stopped.

In Fig. 3, as in Fig. 1, it is assumed that low pressure refrigerantvapor is flowing to the compressor from the tube 30, as indicated by thesolid arrow and that high pressure refrigerant vapor is being dischargedthrough the tube 50 as indicated by the solid arrow. This means that therotor is being driven counterclockwise, as indicated by solid arrow, andthat there is high pressure refrigerant vapor in thc tube 102 whichleads to the check valve 104. This pressure holds the check valve 104closed and thereby through the medium of the rocker 106 the check valve108 is held open. Suction vapor is thus free to enter the compressorthrough the suction port 24 and by way of the branch tube 110 and theport 18. Low pressure refrigerant vapor enters the increasing clearancepocket between adjacent blades 52 and 54. This clearance pocketincreases in volume after passing out of communication with the firstinlet port 18, but soon thereafter it comes into open communication withthe port 24 which extends a considerable angle on each side of thevertical center line. Suction vapor will continue to enter the arcuatecompression space between blades after this space has started to reducein volume, but before there is any appreciable back flow of vapor fromthe compression space into the elongated port 24 this port will be cutoff by blade 54. From this point on the compression space decreases involume and substantially all of the vapor is discharged into the tube102. After the blade 54 has passed the port 28 there will be a returnflow of high pressure vapor into the next compression pocket but notbeyond it. It is thus seen that the customary discharge check valve isnot required in the port 28.

The valve 104 will be held firmly closed by high pressure refrigerantvapor as long as the compressor is operated counterclockwise asindicated by solid arrow in Fig. 3. Due to the arrangement of the tubes102 and 50 it will be seen that oil is centrifugally separated from thedischarge vapor to collect in the chamber 112 ahead of the closed checkvalve 104. This oil remains so trapped until the next idle period of thecompressor, at which time it will flow into port 24 or port 28 andreenter the compressor when next started in its reverse direction ofrotation.

As shown in Fig. 3 the valves 104 and 108 are each hinged to 106 and 108is additionally supported by one of the ears 109 formed on 106, thus theopen valve 108 and the rocker 106 exert gravitational forces tending toopen the valve 104, and their neutral position of rest is with eachvalve partly opened. It will be seen in Fig. 3 that there is only asmall clearance between each valve and the recess which it enters in itsneutral position. In the event of vapor flow toward the valve 104 fromthe tube 102 this valve will be pushed closed and the valve 108 pushedto its position of maximum opening, thus no matter in which directionthe compressor is started the valves 104 and 108 will adjust themselvesto the proper relationship which allows suction Vapor flow to the port24 from the low pressure side of the system and stops flow to port 24from the high pressure side of the system.

As shown in 'Fig. 3, with counterclockwise rotation of the compressorrotor 26, high pressure refrigerant vapor is being discharged at-theport 28 to the tube 102. which leads upward to the chamber 112, thischamber being stopped off from the port 24 by the valve 104 which isclosed, hence the high pressure refrigerant vapor is delivered to thetube 50 which leads to the heat exchanger 12, now serving as thecondenser of the system. Condensed refrigerant flows through therestrictor 14 to the heat exchanger 16, now serving as an evaporator,and the evaporated refrigerant returns through the tube 30 to thechamber 114, which is now serving as a suction chamber. The refrigerantvapor is free to flow through the tube to the primary intake port 18 andpast the open valve 108 to the secondary intake port 24.

When the compressor is stopped the pressure within the system willsubstantially equalize due to the open restrictor 14, to the fact thatthe compressor may be turned in reverse by high pressure vapor from heatexchanger 12 and to the absence of centrifugal force allowing vapor topass the vanes carried by rotor 26. The weight of the rocker 106 and ofthe open valve 108 now cause the rocker 106 to drop to its neutralposition at which both valves 104 and 108 are open. In this neutralposition each valve enters its counterbore 116 where it offersconsiderable resistance to vapor flow without closing tightly.

Assuming now that the compressor is started in the direction of rotationindicated by the dotted arrow on the rotor 26, either by reversing themotor which drives the shaft 62 or by the use of a reversing mechanismbetween this shaft and its source of power. The suddenly applied torquecauses the body of the compressor, which is mounted on flexible supports118, to rotate slightly so the right at the instant of starting. Therocker 106 and the two valves pivoted thereto will, due to theirinertia, lag behind the sudden clockwise jerk of the compressor bodythus causing the valve 108 to close while at the same instant vapordischarged through the port 10 to the tube 110 impinges upon the valve108 to aid in holding it closed until the pressure within the chamber114 builds up to positively hold the valve 108 closed.

This closing of the valve 108 causes the valve 104 to be lifted fartherfrom its seat and clear of its counterbore 116 so that suction vapor isnow free to flow from .the tube 50 to the auxiliary intake port 24 aswell as to port 28, which now becomes the primary suction port. Thisclockwise rotation of the compressor causes the heat exchanger 16 tobegin operation as the condenser of the system. Liquid refrigerant nowflows to the left through the restrictor 14 as indicated by the dottedarrow and it evaporates in the heat exchanger 12, which now serves asthe evaporator of the system, delivering refrigerant vapor to the tube50, which is now serving as the suction tube. Suction vapor is freeto'enter the main suction port '28 of the compressor and also'to passthe open valve '104 from the chamber 112 to the auxiliary suction port 25.

It is thus seen that the ports 18 and 28 have exchanged their functionsand now serve as discharge and suction ports respectively, whereas theauxiliary suction port 24 continues to operate as the auxiliary suctionport, being open to heat exchanger 12 instead of to heat exchanger 16.This use of the auxiliary suction port to receive vapor from the sameevaporator from which vapor is flowing to the active suction port 13 or28 is suitable for a system of the heat pump type in which reversedoperation may continue for several hours instead of for a few minutes asexplained in connection with Fig. 1.

:Fig. 1 reprments the multiple effect use of the con.- pressor and itsuse for the purpose of defrosting the colder evaporator, whereas in Fig.3 the same principle is shown as utilized in an air conditioning systemof the so-called reverse cycle type, which either heats or cools theroom. In the latter case there is no need for two distinct evaporatingtemperatures and normally neither one of the two heat exchangerscollects frost during its operation as the evaporator of the system. Inboth cases gravity, inertia and pressure differences combine to actuatethe valves, the required one being held closed by refrigerant pressureduring operation of the compressor in either direction. The valvemechanism 34 of Fig. 1 might be mounted on the compressor or on itscasing and actuated by the sudden applied torque, as explained inconnection with Fig. 3, or the valve mechanism of Fig. 3 might bemounted independently of the compressor and operated solely byrefrigerant flow, as is the valve 34 of Fig. 1.

Assuming that the compressor of Fig. 3 is incorporated in a sealed unitand rigidly connected with the stator of an electric motor enclosed bythe same sealed casing, it will be seen that the direction of thestarting jerk ap plied to the compressor body is now in the oppositedirection'from that of rotation of the motor rotor, the shaft 62 and thecompressor rotor 26, due to the resultant torque being applied throughthe motor stator to the body of the compressor, with or withouttransmission of such resultant torque through the casing which enclosesthe motor and the compressor.

Fig. 4 shows how the principle of actuating a reversing valve by meansof inertia can be applied to a conventional piston type compressor toaccomplish the result ofrFig. 3. Assuming that suitable provisions havebeen made for lubrication, a reciprocating compressor of the piston typemay be driven in either direction of rotation, but the reversal ofrotation does not reverse the direction of refrigerant flow. The valvemechanism seen in Fig. 4 is intended to replace the usual cylinder headof an open type reciprocating compressor in which both intake anddischarge ports are through the regular valve plate of the compressor.The plan is to design a replacement cylinder head to be bolted on top ofthe valve plate in place of the original cylinder head which isconnected with the suction and discharge tubes, thus converting aconventional rotary or reciprocating compressor into a flow-reversingcompressor.

The special cylinder head includes the valve body which is shown insection as 130 in Fig. 4. The chamber 132 connects with the chamber intowhich high pressure vapor flows from the regular discharge valve of thecompressor, and the chamber 132 connects in a similar manner with thechamber from which suction vapor is drawn through the regular intakevalve of the compressor. It is therefore only necessary to consider Fig.4 as a top view of a conventional reciprocating compressor of which thecrank shaft is indicated at 136. The actual valve mechanism is verysimilarto the one shown in Fig. 6 of my copending U.S. patentapplication Serial No. 50,101, filed Sept. 20, 1948, noW'Patent No.2,672,016, but the actuating mechanism shown in Figs. 7 and 8 of thisearlier patent application of mine is omitted. The valve stems 138 and140 are supported by guides 142 and 144- respectively and are free toslide therein. We thus have a pair of check valves 146 and 148 in thedischarge chamber 132', but these check valves are rigidly connectedtogether so that one must open when the other is closed. Likewise wehave a pair of check valves 150- and 152 arranged to close one or theother of two ports which lead into the chamber 134- from which suctionvapor flows to the regular intake valve of the compressor.

Assume now that the valves are as shown in Fig. 4 or in neutralpositions, none being fully closed, that the compressor body is mountedon springs or other flexible supporting means 118, as shown in Fig. 3,and that torque is suddenly applied to the shaft 136 in the directionindicated by the solid arrow. During the first compression stroke of apiston in the compressor the compressor body will jerk suddenly to theright, causing valves 146 and 152 to close. This compression strokedelivers compressed vapor into the chamber 132, thus holding the valve146 closed and the valve 148 open so that the discharge vapor can flowfreely past valve 148 into the chamber 154 and out through the port 156which now serves as the discharge connection leading to the condenser.The discharge vapor filling the chamber 154 aids in holding the valve152. closed so that the valve 159 is held open, allowing vapor to bedrawn from the port 158 through the chamber 161i and past the valve 150into the chamber 134, which is connected with the regular intake port ofthe compressor. So long as the compressor continues to operate in thisdirection, each of the valves 146 and 152 is held closed by highpressure refrigerant, thereby holding their mating valves 148 and 150open. The result is to deliver compressed refrigerant vapor to condenser16, where it condenses and then flows through restrictor 14 to theevaporator 12 from which its vapor flows to port 158. When thecompressor is stopped the high and low side pressures may be allowed toequalize or not as desired. They will substantially equalize if avapor-lock restrictor is used as shown in Fig. 4. Should the next startof the compressor be in its opposite direction of rotation the resultwill be to close the valves 148 and 150 and to open valves 146 and 152,thus coming back to the position shown in Fig. 4 with flow as indicatedby the solid arrows.

As in Figs. 1 and 3 the secondary evaporator 68 of Fig. 4 is cooled onlywhen its condenser 70 is colder than 68, with the result thatrefrigeration is suspended in the secondary evaporator 63 while theevaporator 12 is being defrosted. This arrangement is suitable for usein a two-temperature household refrigerator. The arrangement of Fig. 4,with the secondary system 6$-76 omitted, is also suitableforreverse-cycle air conditioning systems, as the conventionalreciprocating compressor is equally efficient in its two directions ofrotation and may be operated for long periods in either direction,assuming that proper provision has been made for lubrication.

Again it will be understood that in the event that the compressor ofFig. 4 is enclosed within a sealed unit and rigidly associated with thestator of the motor, as is customary, using either internal or externalspring mounting of the sealed unit, the sudden jerk which moves thevalves will be caused by resultant torque, hence the valves will operatein exactly the reverse manner. The effect however is the same becausehigh pressure refrigerant is delivered through port 156 when thecompressor is started in one direction and it is delivered through portwhen the compressor is started in the opposite direction. In each casethe former discharge tube becomes the suction tube. It is also withinthe scope of this invention to mount the inertia-actuated valves on themotor which drives the compressor or on the casing of a sealed unit. Inany case the valve or valves can be actuated by inertia due to startingof the compressor.

Fig. needs no explanation, being a detail section of Fig. 4 to show thatvalve guides 142 and 144 are a part of the casting 130.

Fig. 6 shows a system similar to that of Fig. 1, but employing aconventional reciprocating compressor 162 of the multiple-effect type,i.e. one having two suction ports for two separate suction pressures.Since this is not a reversible compressor the reversal of flow isobtained by means of a valve mechanism such as shown in my co-pendingUS. patent application Serial Number 45,343, filed August 20, 1948, nowPatent No. 2,654,227. Another change from Fig. 1 is that the twopressure reducing devices are located in branch lines instead of inseries. Fig. 6 also shows the use of a clock-actuated switch to causedefrosting to occur at a preselected time, preferably between midnightand daybreak.

The switch 164 includes blade 165 which is normally actuated by theclock 166 on a time cycle, but may also be operated manually whenoccasion requires. The lifting of this switch blade 165 breaks thecircuit through wire 173 and the switch 174 regardless of the positionof its blade 175 and energizes the circuit through wire 167, thesolenoid 168 and wire 169 to lift the valves of 170 to their defrostingpositions, as explained in the earlier application above mentioned. Atthe same time the switch closes a circuit through the wires 172 and 172'to short out the thermostatic switch 174 and start the compressor motor176 if it is not already running. The clock mechanism allows the switch164 to drop to the position shown at the end of a short period which isestablished just long enough to insure that the freezer evaporator 12 isdefrosted. This allows return of the valves to their normal positions asshown, due to the combined weight of the movable parts of 170 and 168which is ample to overcome the upward liquid pressure on the valveswhich were closed during the defrosting operation. As an additionalprovision to insure the downward movement of the valves due to gravitywhen the solenoid 168 is de-energized I propose to employ loose fits forlost motion in the pivots which connect these valves with the armatureof solenoid 168.

The valve assembly 34 and 66 of Fig. 1 could be used in Fig. 6 in thesame manner, but I have shown the warmer evaporator 20 fed with liquidthrough the branch tube 178 and expansion valve 180, thus eliminatingthe valve assembly 34. Normal flow of refrigerant is as indicated bysolid arrows, the restrictor 14 being designed to produce a greaterpressure drop than the expansion valve 180 so that evaporator 12operates at below freezing while evaporator 20 operates at anon-frosting temperature or defrosts itself during each idle period.

Closing the defrost switch 164 produces reverse cycle operation ofevaporator 12 and condenser 16 without feeding either liquid or vapor toevaporator 20. Any liquid in evaporator 28 at the time defrosting startsis evaporated therein and the vapor flows through tube 66 to theauxiliary inlet of the compressor as in Fig. 1. There will besubstantially no flow of liquid through the expansion valve 180 duringthe short defrosting operation, though there may be some if the pressurein evaporator 20 is pulled down to below that of the condenser 16 whichoperates as a low pressure evaporator during the defrosting ofevaporator 12. Dotted arrows indicate the flow during the defrostperiod. In the event that only one evaporator is required or thesecondary system 68-70 is used, the evaporator 20 may be omitted alongwith expansion valve 180 and tubes 178 and 60. This arrangement allowsthe use of any conventional compressor in place of the multiple-suctioncompressor 176.

The thermostatic switch 174 may be equipped with two bulbs so as to openwhen both the space cooled by evaporator 12 and the space cooled byevaporator 20 have been pulled down to their required temperatures. Forsuch use I show two bulbs connected with the thermostat 174 and it isassumed that the thermostat is 1Q charged with a volatile fluid in suchquantity that the bulb associated with evaporator 20 will contain onlyvapor at the cut-out point.

The secondary system 6870 operates as described in connection with Figs.1, 3 and 4 and may or may not be provided with the thermostatic controlvalve 182.

Fig. 7 shows a modified electrical system particularly suited for use inair conditioning or when the reversecycle periods are apt to last forhours instead of minutes. The blade 183 of switch 184 is actuated inresponse to temperature changes of bulb 186, which is located in thespace where temperature is to be controlled. A rise of temperature ofbulb 186 moves the blade 183 of switch 184 downwardly, thus energizingthe motor 176 through wires to start and 185' to run without energizingthe solenoid 168. Thus operation of the system is started normally withflow as shown by solid arrows, causing 12 to operate as the evaporatorand 16 as the condenser. When the switch blade is moved in the oppositedirection, either manually or in response to a drop of temperature ofthe bulb 186, the motor 176 and solenoid 168- are both energized throughwires 187, 187 and 185 so that the flow of refrigerant follows thedotted arrows, causing 12 to function as a condenser and 16 as anevaporator, thus heating the controlled space. It will be seen howeverthat the solenoid 168 remains energized only so long as the startingcircuit breaker 188 remains closed with its blade 189 in the solid lineposition. In this case the armature of the solenoid and the movableparts of the valve assembly 170' are made light in weight relative tovalve port sizes so that the high side pressures etfec-- five on thevalves by the time the circuit breaker opens will be ample to hold thevalves in the posit-ions to which they have been moved by the solenoid.Thus it is only necessary to lift the valves at the start of the run andthey will thereafter be held in their lifted positions by high siderefrigerant pressure until the next time the compressor is stopped. Assome time will always elapse between the need for heating and the needfor cooling, the pressures within the system will equalize to allow thevalves to drop before the system is restarted.

The wiring of Fig. 7 puts the solenoid 168 in series with the startingwinding of the motor 176, which is permissible with a solenoid windingwhich ofiers little resistance to fiow of current. The solenoid and thestarting circuit could be wired in parallel, as they are in Fig. 6, at aslight additional cost but this is not considered necessary.

The secondary system 687t) of Figs. 6 and 7 operates as in Figs. 1, 3, 4and 5, cooling evaporator 68 whenever evaporator 12 is cooled. Thesecondary system remains idle when the evaporator 12 is functioning as acondenser.

Figure 8 is a bottom view of a preferred design and location of a sealedmotor-compressor unit 10, such as shown in Figs. 1 to 4 inclusive. Itwill be understood that the lubricating system of Fig. 2 and the valvesof Fig. 3 may be modified to fit the vertical axis arrangement of Pig.8, as by putting the valves and ports 18, 28 and 24 of Fig. 3 in the endplate '72 of Fig. 2. The casing of unit 10 is flexibly mounted on therear wall of a refrigerator and provided with parallel fins 192 insteadof the usual radial fins. This is to reduce the horizontal dimensionbetween the back of the refrigerator 194 and the wall 195 of the room.It is highly desirable to locate the motor-compressor unit in thismanner and to keep one of the horizontal dimensions down to the minimumwhich allows use of a suitable motor. One of the reasons for preferringa two-pole motor, is to reduce its diameter for use in this location.This arrangement puts the fins in vertical planes, thus adapting theunit for cooling by gravity circulation of air upwardly over it.

The tube 50, which normally carries suction vapor, is preferablyconnected as at 60 of Fig. 2, thus the motor is normally cooled bysuction vapor and high pressure vapor 1i flows through the casing duringthe short defrost period only. A port not shown connects the chamber 112(Fig. 3) with the interior of the motor casing of Fig. 8. I propose tolocate the unit It or a portion of the condenser near the bottom of thecabinet to provide heat for evaporating drip water to ambient air.

The electrical system of Fig, 8 may be similar to that of Fig. 6, exceptthat the switch 164 will also reverse the motor, normally closing themotor circuit through the thermostatic switch 174 while during defrostit opens this circuit and closes the one which reverses motor rotation.In the event that defrosting is to be controlled in response to frostaccumulation, door openings, a temperature change, manually or otherwisethan on a time cycle the clock may be omitted.

In the event that the system of Fig. l is to be used in Fig. 8 the tubes102 and 110 will disappear and we will see tubes 30 and 50 enter thenear (bottom) end of while tube 60 comes out the back of the cabinet anddisappears on the far (top) end of 10, where it enters the casing, as inFig. 2. This eliminates the valves of Fig. 3 and substitutes the valvesof Fig. 1, which are preferably located inside of or adjacent to theirrespective refrigerated spaces within the refrigerator cabinet.

The word inertia is used in this specification and the appended claimsas defined in Websters Dictionary thus: That property of matter by whichit tends when at rest to remainso, and when in motion to continue inmotion, and in the same straight line or direction, unless .acted on bysome external force.

It will be understood that a change of design from one in which thecompressor body is rigidly connected with the stator of the motor, andthe jerk is caused by resultant torque, to one in which the compressorbody is separate from the motor stator and the starting jerk is causedby frictional drag, or vice versa, will not change the fact of thevalves of Fig. 3 or 4 being actuated by their inertia. It would howeverchange the marking of switch 96 as used in either Fig. 3 or Fig. 4 andin Fig. 3 it would call for crossing the tubes I02 and 1.10 to connectwith 114 and 112 respectively. Instead of L (left) and R (right) theswitch might be marked C (cooling) and D (defrosting) to match thedetailed design.

The showing of two bulbs for switch 174 in Fig. 6 will be understood byreference to Fig. 10 of my issued US. Patent No. 2,349,367 or to themultiple bulbs of switch 83 in Fig. 13 of my U. S. Patent No. 2,359,780.

The modifications here shown represent only a few typical designs whichutilize the principles of this invention, the main features of which areobtainable in designs having many other modifications of mechanicaldetails.

I claim:

1. In a refrigerating system employing a volatile refrigerant, acompressor, means for starting said compressor in either direction ofrotation, a valve for controlling flow of said refrigerant, a seat forsaid valve, and means associated with said valve for moving it relativeto its seat, said means comprising a mass which is movable relative tothe main body of said compressor and thus caused by its own inertia tomove the valve in one direction relative to its seat when the compressoris started in one direction of rotation and in the opposite directionwhen the compressor is started in the reverse direction of rotation.

2. In a refrigerating system, a compressor, an intake port for saidcompressor, means forming two passages leading to said intake port,valve means for stopping flow to said port from said passages one at atime, and means responsive to the flow of refrigerant vapor from saidcompressor for actuating said valve means.

3. In a refrigerating system, a compressor, said compressor beingreversible as to direction of its pumping action, an intake port forsaid compressor, means form- I2 ing two passages leading to ,said intakeport, valve means for stopping flow to said port from said passages oneat a time, and means actuated by flow of refrigerant vapor from-saidcompressor for actuating said valve means to stop flow from one of saidpassages for one direction of said pumping action and to stop flow fromthe other of said passages for the other direction of said pumpingaction.

4. In a refrigerating system, a compressor, a control device forreversing the direction of rotation of said compressor to reverse itsdirection of pumping action, a valve, a seat for said valve, and meansfor utilizing inertia to cause said valve to move relative to its seatat the instant the compressor is started.

5. In a refrigerating system, a motor-compressor unit including flexiblesupporting means, means for starting said compressor, a valve and a seattherefor associated with the said compressor, and inertia means foractuating said valve to move it relative to its seat as a result oftorque reaction on the body of said unit caused by the starting of saidcompressor,

6. In a refrigerating system of reversible heat pump type, a compressor,a motor for driving said compressor in either direction of rotation, aninlet port of said compressor which serves as inlet port regardless ofthe direction of compressor rotation, a pair of passages leading tosaidinlet port, valve means for closing one at a time of said passages whileopening the other, a mass associated with said valve means, meansutilizing the inertia of said mass at the moment of starting saidcompressor in either direction to actuate said valve means in accordancewith the starting direction of rotation, and means for employing thedischarge pressure of said compressor to hold said valve means in theposition which maintains the closure of one of said passages duringcontinuous operation of the compressor in the direction in which it wasstarted.

7. In a refrigerating system, a compressor, means for starting saidcompressor, a refrigerant passage, a valve adapted to close saidpassage, and means mounting said valve so that it movably responds todual influences, one of said influences being refrigerant flow and theother of said influences being an inertia resultant of torque suddenlyapplied to said compressor.

8. In a refrigerating system, a rotary compressor having two inlet portsfor low pressure vapor and a discharge port, a suction conduit having abranch leading to each of said inlet ports, means for reversing saidcompressor to cause said discharge port to become an inlet port and oneof the first said inlet ports to'become a discharge port, and a checkvalve in the branch of said suction conduit which leads to the other oneof the first inlet ports, whereby said branch is closed to flow ofdischarge vapor to said other one of the first said inlet ports whensaid compressor is reversed.

9. In a refrigerating system employing a volatile refrigerant, a pair ofheat exchangers of which one acts as a condenser and the other acts asan evaporator, a compressor for supplying refrigerant vapor to the heatexchanger acting as a condenser and drawing vapor from the one acting asan evaporator, control means for stopping said compressor and restartingit in either direction of rotation, a valve for changing the path ofrefrigerant flow when said compressor is restarted in the oppositedirection of rotation from that in which it was last operated, saidchanging of the path causing the first said one of the heat exchangersto act as an evaporator and said other to act as a condenser, andinertia means responsive to the starting of said compressor only duringacceleration thereof for actuating said valve.

10. In a refrigerating system, a reversible compressor, andinertia-actuated valve means for establishing the direction ofrefrigerant flow in said system in accordance with compressor rotationeach time the compressor is started or reversed in its direction ofrotation.

11. In a refrigerating system, a compressor, reversible driving meansfor said compressor, and a valve closed by an inertia force which iseffective only while said compressor is being accelerated, said valvebeing thereafter held closed by the discharge pressure produced by saidcompressor during its operation.

12. In a refrigerating system employing a volatile refrigerant, twoevaporators, a condenser, two pressure reducing devices including onefor each of said evaporators, a first one of said devices being of atype adapted to control refrigerant flow in either direction, the otherof said devices being pressure-responsive and adapted to regulate theflow of refrigerant in one direction only, and 4 means for reversing theflow of refrigerant in a portion of said system whereby one of saidevaporators is caused to serve as a condenser for the purpose ofdefrosting it while the first said condenser serves to evaporate liquidrefrigerant which it receives from the defrosting evaporator now servingas a condenser by way of said first one of the pressure reducingdevices, the other of said evaporators meanwhile having its inletstopped.

13. A fluid flow control valve for use in a refrigeration system of thetype having a reversible compressor and means for alternatively drivingsaid compressor in its forward and its reverse directions, said valvecomprising a body member for mounting on an element of the system thatmoves in one direction in response to starting of the compressorforwardly and moves in a different direction in response to starting ofthe compressor reversely, and a valve member movable relative to saidbody member by inertia in response to movement of the element caused bystarting of the compressor in a predetermined direction.

14. A fluid flow control valve for use in a refrigeration system of thetype having a reversible compressor and means for selectively drivingsaid compressor in one or the other of two directions, said valvecomprising a body member for mounting on an element of the system thatmoves in one direction in response to starting of the compressorforwardly and moves in a different direction in response to starting ofthe compressor reversely, and a valve member movable relative to saidbody member by inertia in response to movement of the element caused bystarting of the compressor in a predetermined direction, said valvemember being arranged when it is moved by inertia to one position to beheld in said one position by fluid pressure within said valve body.

15. A fluid flow control valve for use in a refrigeration system of thetype having a reversible compressor and means for selectively drivingsaid compressor in a first or a reverse direction, the compressor havingan outlet port and an inlet port, and the direction of fluid flowthrough said outlet and inlet ports being constant regardless of thedirection of drive of the compressor, said valve comprising a bodymember for mounting on an element of the system that moves initially inone direction in response to forward starting of the compressor andmoves initially in a direction different from said one direction inresponse to reverse starting of the compressor, said body memberdefining a chamber and a first port communicating therewith forconnection to one of the ports of the compressor, said body also havinga second port and a third port communicating with said chamber, and areciprocatable valve member for alternatively closing one of said secondand third ports in response to a movement of the element on which saidbody member is mounted caused by starting of the compressor, the inertiaof said valve member being effective to shift it relative to said bodymember in response to movement of the element caused by starting thecompressor in a direction opposite from the direction in which it waslast operated.

References Cited in the file of this patent UNITED STATES PATENTS2,295,124 Mufily Sept. 8, 1942 2,309,797 Stickel Feb. 2, 1943 2,342,174Wolfert Feb. 22, 1944 2,343,514 McCormack Mar. 7, 1944 2,414,339 SkaggsJan. 14, 1947 2,497,903 Muflly Feb. 21, 1950 2,605,050 MacDougall July29, 1952 2,638,123 Vargo May 12, 1953 UNITED STATES PATENT OFFICECERTIFICATION OF CORRECTION Patent 2,976,698 March 28, 1961 Glenn MufflyIt is hereby certified'that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 4, line 43, for "reserve" read reverse column 9, line 42, for"assembly" read asemblles Signed and sealed this 8th day of August 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

